1. Field of the Invention
This invention relates generally to hand-held power tools, and more particularly, to an auxiliary rotary tool drive apparatus that is mounted on, or an integral component of, a hand-held rotary power tool, such a rotary drill, and has an extendable and retractable auxiliary drive shaft and a gear assembly that is selectively operatively engaged with the drive shaft and gear assembly of the power tool and driven thereby using only the hand grasping the drill for driving screws, fasteners, bits or other work performing members attached to the auxiliary drive shaft without having to move or remove the existing drill bit or work performing member from the chuck of the power drill.
2. Background Art
As used herein, the term “rotary power tool” means a tool having a housing containing a driving motor and a drive train connected with a power transmitting shaft (drive shaft, spindle or anvil) that extends forwardly from the housing and may have a chuck or holding member at its outer end which grips a work performing member to be rotatably driven. Power tools are classified as either stationary or portable, where portable means “hand-held”. Common power tools include drills, drivers, drill/drivers, screwdrivers, and hammer drills or impact drills. In hammer drills or impact drills, the drive shaft is referred to as an “anvil”. As used herein, the terms “chuck” or “holding member” means any device that holds bits, rotating tools, fasteners or other work performing members to the power transmitting shaft of the power tool. As used herein, the term “work performing member” can include such devices as drill bits, screws, fasteners, screw drivers, nuts, bolts, finishing tools, and other rotary devices which can be releasably engaged in the chuck or holding member connected to the rotary power transmitting shaft (drive shaft, spindle or anvil). As used herein, the terms “drive shaft” and “auxiliary drive shaft” means the power transmitting shaft, spindle, or anvil of the power tool and the auxiliary rotary tool drive apparatus, respectively.
The task of a driving a screw or fastener into a surface typically involves first drilling a pilot or starter hole, then driving the screw or other fastener into the previously drilled pilot hole. These two tasks, drilling and driving, require either using two different bits in the same drill, or using two drills with one utilizing a drill bit and the other utilizing a screw driving bit.
If a single conventional power drill is used, at least one bit change is needed to complete both tasks. This requires loosening and removing the drill bit from the chuck and inserting the appropriate screw driver bit and tightening the drill chuck. Use of a double ended bit held in a quick change adapter clamped in the drill chuck, is somewhat easier and quicker, however, it still requires releasing, removing, turning, and reinserting the dual ended bit.
Both of these scenarios are time consuming and changing bits greatly increases the probability of dropping and losing a bit or other rotary tool. It also requires the use of two hands. Since these procedures require both hands to change the bit, the user is precluded from grasping a secure structure while completing the bit changing process, which can be potentially dangerous if done on a ladder, scaffold, or any high or unstable platform.
Using two drills, the first equipped with a drill bit and the second equipped with a screw driving bit, requires repeatedly laying down the first drill and picking up the second. This process of changing back and forth between the required drills is time consuming and quickly becomes tedious, particular when it is done frequently or repetitively.
Others have attempted to correct the above-mentioned problems. However, none appear to have successfully solved all the problems, nor appear to be capable of drilling a pilot hole and driving a screw immediately in the hole using only one hand and without turning or regrasping the drill or tool.
There are several patents directed toward various rotary tools with more than one output; however, they all share similar drawbacks when faced with the task of drilling a hole and subsequently driving a screw in the hole. They require the use of two hands and regrasping the tool to drill a hole and subsequently drive a screw in the hole.
U.S. Pat. No. 1,650,911 to Schneider discloses a rotary power tool having a dual drive output that is adaptable for use as a drill, a screw driver, a tapper and a wrench. The disadvantage of this tool is that the toolheads extend therefrom in the same direction and operate at roughly the same working length. For example, in order to use the screw driver, the chuck containing the drill bit must be loosened and the drill bit must be removed to prevent it from contacting the surface into which the screw is to be driven.
U.S. Pat. No. 1,750,957 to Fowler discloses a drill attachment having extensions therefrom in opposite directions. The drill of one extension rotates clockwise and the chuck or attachment of the other extension rotates counter-clockwise as viewed from the main body of the tool. The tool is not able to drill a hole and subsequently drive a screw in the hole without first reversing shaft rotation and releasing, turning and regrasping the tool, which is a cumbersome and time-consuming process.
U.S. Pat. No. 4,299,004 to Lancaster discloses a powered hand tool for household cleaning operations having two drive shafts for polishing wheels extending therefrom in perpendicular directions. The polishing wheels turn in opposite directions as viewed from each of their drives, and the drives are not extendable. In addition, the perpendicular drives could result in interference when working in a corner. These factors would make applying this invention to drilling and rotary fastening very impractical and inconvenient.
U.S. Pat. No. 4,810,916 to McBride teaches a rotary power tool that includes two extensions in opposite directions therefrom. The power tool may utilize a screwdriver bit at one extension and a drill at the other extension. Although both the screwdriver bit and the drill bit are rotatable in the same working direction as seen looking toward each driven portion, it still requires two hands and regrasping to accomplish drilling a hole and subsequently driving a screw in the hole. This results in a cumbersome and time-consuming process.
There are also several patents directed toward various power hand tools that provide a magazine carrying several different bits or rotary tools and a way of selecting the one needed by aligning the bit or tool with a chuck axis, moving the bit or tool into place, and tightening the chuck. If the chuck already contains a bit or tool, you must first loosen the chuck to remove the bit or tool and return it to the magazine before utilizing a different bit or tool. There are also several patents directed toward hand-held power drills having a mechanism that operates similar to a rifle “bolt-action” to selectively engage a driver bit with the primary drive shaft that also drives the chuck that carries a drill bit, and patents having a rotatable magazine, similar to a revolver, that carries a plurality of drill bits from which a single bit is selected and engaged in the chuck driven by the primary drive shaft, and patents directed toward the turret type power tools having a turret that carries dual or multiple chucks that can be selectively engaged with the primary drive shaft.
U.S. Pat. No. 5,065,498 to McKenzie discloses a drill having a magazine containing a multiplicity of bits from which a single bit is selected using a bolt action, but only one drive shaft. The drawback to this method is that it is cumbersome to use and requires two hands to operate and change the selected rotary tool.
U.S. Pat. No. 4,604,005 to Russ discloses a portable selector drill having a rotatable magazine, similar to a revolver, which carries a plurality of drill bits from which a single bit is selected and is driven forward into the chuck driven by the primary drive shaft.
U.S. Pat. No. 2,679,770 to Carter et al discloses a portable tool selective drill having a rotatable housing that is mounted at the front end of the drill and replaces the existing chuck. The housing carries a plurality of drill bits and is manually rotated to engage and drive the selected bit with the primary drive shaft.
U.S. Pat. No. 6,007,277 to Olson et al discloses a portable selector drill having a rotatable magazine, similar to a revolver, but only a 120° segment, that carries a plurality of drill bits from which a single selected bit is driven forward by a cable mechanism into the chuck and driven by the primary drive shaft.
U.S. Pat. No. 5,346,453 to Rivera-Bottzeck discloses a portable electric drill having a rotatable cylindrical magazine within the drill housing for storing a plurality of bits, the magazine is rotated to bring a selected magazine bore in alignment with the central bore of a chuck assembly at the front of the drill. A flexible cable is slidable by hand between forward and rearward positions to eject a tool bit element from the magazine to the chuck and to return a tool bit from the chuck to the magazine.
As previously mentioned, the drawback to these inventions is that they are all cumbersome to operate and require two hands to operate and change the selected rotary tool.
Therefore, a need exists for a way to drill a hole and subsequently drive a screw, fastener, or other work performing member, without changing bits or other work performing members, swapping drills, and without releasing, turning, or regrasping the tool handle grip.